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KVM: VMX: Enable and initialize VMX TSC scaling
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This patch exhances kvm-intel module to enable VMX TSC scaling and
collects information of TSC scaling ratio during initialization.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Haozhong Zhang authored and Paolo Bonzini committed Nov 10, 2015
1 parent 27cca94 commit 64903d6
Showing 2 changed files with 19 additions and 1 deletion.
3 changes: 3 additions & 0 deletions arch/x86/include/asm/vmx.h
Original file line number Diff line number Diff line change
@@ -73,6 +73,7 @@
#define SECONDARY_EXEC_ENABLE_PML 0x00020000
#define SECONDARY_EXEC_XSAVES 0x00100000
#define SECONDARY_EXEC_PCOMMIT 0x00200000
#define SECONDARY_EXEC_TSC_SCALING 0x02000000

#define PIN_BASED_EXT_INTR_MASK 0x00000001
#define PIN_BASED_NMI_EXITING 0x00000008
@@ -167,6 +168,8 @@ enum vmcs_field {
VMWRITE_BITMAP = 0x00002028,
XSS_EXIT_BITMAP = 0x0000202C,
XSS_EXIT_BITMAP_HIGH = 0x0000202D,
TSC_MULTIPLIER = 0x00002032,
TSC_MULTIPLIER_HIGH = 0x00002033,
GUEST_PHYSICAL_ADDRESS = 0x00002400,
GUEST_PHYSICAL_ADDRESS_HIGH = 0x00002401,
VMCS_LINK_POINTER = 0x00002800,
17 changes: 16 additions & 1 deletion arch/x86/kvm/vmx.c
Original file line number Diff line number Diff line change
@@ -107,6 +107,8 @@ static u64 __read_mostly host_xss;
static bool __read_mostly enable_pml = 1;
module_param_named(pml, enable_pml, bool, S_IRUGO);

#define KVM_VMX_TSC_MULTIPLIER_MAX 0xffffffffffffffffULL

#define KVM_GUEST_CR0_MASK (X86_CR0_NW | X86_CR0_CD)
#define KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST (X86_CR0_WP | X86_CR0_NE)
#define KVM_VM_CR0_ALWAYS_ON \
@@ -1172,6 +1174,12 @@ static inline bool cpu_has_vmx_pml(void)
return vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_ENABLE_PML;
}

static inline bool cpu_has_vmx_tsc_scaling(void)
{
return vmcs_config.cpu_based_2nd_exec_ctrl &
SECONDARY_EXEC_TSC_SCALING;
}

static inline bool report_flexpriority(void)
{
return flexpriority_enabled;
@@ -3133,7 +3141,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
SECONDARY_EXEC_SHADOW_VMCS |
SECONDARY_EXEC_XSAVES |
SECONDARY_EXEC_ENABLE_PML |
SECONDARY_EXEC_PCOMMIT;
SECONDARY_EXEC_PCOMMIT |
SECONDARY_EXEC_TSC_SCALING;
if (adjust_vmx_controls(min2, opt2,
MSR_IA32_VMX_PROCBASED_CTLS2,
&_cpu_based_2nd_exec_control) < 0)
@@ -6178,6 +6187,12 @@ static __init int hardware_setup(void)
if (!cpu_has_vmx_apicv())
enable_apicv = 0;

if (cpu_has_vmx_tsc_scaling()) {
kvm_has_tsc_control = true;
kvm_max_tsc_scaling_ratio = KVM_VMX_TSC_MULTIPLIER_MAX;
kvm_tsc_scaling_ratio_frac_bits = 48;
}

if (enable_apicv)
kvm_x86_ops->update_cr8_intercept = NULL;
else {

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